Explosionproof fitting for electric glowlamps



July 3, 1928." 1,675,837

7 J. BECKMANN EXPLOSION PROOF FITTING FOR ELECTRIC GLOW LAMPS Filed Aug. 15, 1927 I Y fivezfar V Patented July 3, 1928.

PATENT OFFICE.

J'OHANNES BECKMANN, OF ALTONA-OTTENSEN, GERMANY.

EXPLOSIONPROOF FITTINGFOR ELECTRIC GLOWLAMIPS.

Application filed. August 15, 1927. Serial No. 213,055.

This invention relates to improvements in an explosionproof fitting for electric glow-. lamps, such as for instance described in my U. S. Letters Patent No. 1,629,089. The

object of the invention is to overcomecertain drawbacks of said fitting consisting, on the one hand, in the fact that it is possible with open fitting to retract from outside the locking belt for the glow-lamp switch axle 1 and thus to close the circuit in spite of the fitting being open. and, on the other hand, in the fact that with open fitting incompetent persons can get at the inner parts thereof, for instance at the lamp socket and the switch.

To overcome these drawbacks, according to the invention, the pivot of the hinged fitting member is provided with a fixed camdisc which co-acts with a spring-pressed bolt that bears with an abutment thereon against an axially movable spring-influenced bar and thereby secures the locking bolt in the open position of the fitting against its being retracted. Furthermore, on the stationary fitting member a lockable cover is mounted thatis in disengageable connection with the locking means for the movable fitting member.

The accompanying drawing illustrates by way of example a preferred constructional form of the subject matter of the invention Fig. 1 is an underside plan view of the stationary fitting member, partly in section on the line 1-1 of Fig. 2, which 'is a vertical section on the line 2-2 of Fig. 1 showing the fitting in its open position.

Fig. 3 is a similarsection, to that shown in Fig. 2, with the middle part broken away, showing the fitting in'its closed position.

Fig. 4 is a. vertical section on the llne 14ofFig.3,"

Fig. 5 is a vertical section on the hne 55 of Fig. 2, and

Fig. 6 is a vertical section on the line 6-6 of Fig. 3. g

The movable fitting member 2 is hinged by a pivot 3 to the stationary fitting memher 1. The movable fitting member 2 that covers the lamp socket 4 in its closed posi- 'ti'on carries a tappet 7 provided with an 'open-ended keyhole 5, 6 and adapted when closing the fitting to retract the locking bolt 8 until the switch axle 9 enters the round boring 6 of thekeyhole and can thus be turned therein.

The pivot 3 of the hinged fitting member 2 is provided with a fixed cam-disc 10 which co-acts with a spring-pressed bolt 11 that bears with an abutment 12 againsta springinfluenced'movable bar 13. The latter carries at its other end a locking'pawl 14 by which it can pass through a slot 15 in the wall of the casing surrounding the locking bolt 8 and enter a slot in the latter when the same assumes its locking position (Figs. 3 and 4). When the hinged fitting member 2 is being closed, the cam-disc 10 is turned (Fig. 3) seas to allow the spring-pressed bolt 11 to descend and the spring-influenced bar 13 by action of its spring 17 to slide with its pawl 14 out of the slot 16 of the locking bolt 8, so that the latter is retracted against the action of its spring 18 by the tappet 7 of the hinged fitting member 2 and the switch axle 9 can move with its flattening 19 through the slot 5 into the round boring 6 of the keyhole in the tappet 7, whereupon the closure of the fitting (Fig. 3) is effected by turning the switch axle into the position shown inFig. 4 and the lamp is simultaneously switched-on. For openin the fitting, first, the lamp must be switche ofl by means of the switch knob 20 in order to permit the flattening 19 of the switch axle 9 leaving the round boring 6 through the slot 5 in the keyhole of the tappet 7 (Figs. 2 and 5). Then, when opening the hinged fitting member 2, the single parts re-assume again by action of the cam-disc 10 automatically the position shown in Fig. 2. For preventing with o n fitting an access to the inner parts thereo for instance to the lamp'socket 21. and to the switch 22, a lockable cover 23 is arranged on the stationary fitting member 1 and adapted to engage by a pin 24 thereon into a boring in the wall of said fitting member 1 while it carries at its opposite side an inwardly projecting bolt 25 by which it is in disengageable connection with the switch axle 9, for which purpose said bolt carries an eye-shaped head 27 with a round boring 28 andHan open slot 29 at its top, while the switc axle 9 is provided with a flat extension 26 that in its vertical position can be introduced through the slot 29 into the round boring 28 of the eye 27.

With closed fitting and in t 1e locked position of the parts (Fig. 3), the switch axle 9 assumes the position shown i Fig. 3.

With open fitting (Fig. 2), the switch axle 9 is so turned that its flat extension 26 lies horizontally in the round boring 28 of the eye 27 of the bolt 25 whereby the cover 23 is locked.- In this locked position of the cover 23, the inner parts of the fitting are inaccessible in spite of the fitting being open.

What I claim is 1. In an explosionproof'fitting for electric glowlamps, the combination with a stationary fitting member, a movable fitting member hinged to the former, a glowlamp switch axle in said stationary fitting member, and a slotted locking bolt arranged in the stationary fitting member and adapted with open fitting to lock' the switch axle against turning, of means for securing said bolt in its locking position with open hinged fitting member.

2. A fitting as specified in claim 1, in which said means consists of a fixed camdisc on the pivot of said hinged fitting member, a spring-pressed bolt co-acting with said cam-disc, a spring-influenced movable bar acted upon by said bolt, a pawl on the free end of said bar adapted with open hinged fitting member to engage in the slotted looking bolt by action of said cam-disc.

3. In an explosionproot fitting for electric glowlamps, the combination with a stationary fitting member, a movable fitting member hinged to the former, a glowlamp switch axle in said stationary fitting member, and a slotted-locking bolt'arranged in the stationary fitting member and adapted with open fitting to lock the switch axle against turning, of means for preventing an access to the inner parts of the fitting with open hinged fitting member.

4; A fitting as specified in claim 3, in which said means consist of a fiat extension on said switchaxle, a lockable cover arrange on the stationary fitting member, a pin on said cover engaging in the wall of said stationary fitting member, an inwardly projecting bolt at the other side of said cover and having an openended keyhole at its top end adapted to lockably engage with said fiat switch axle extension in the open position of the hinged fitting member.

In testimony whereof I have hereunto set my hand.

J OHANNES BECIQ'IANN. 

